The present invention relates to a method for filling flexible containers having at least two lifting loops, and an apparatus for carrying out the method which also comprises making the filled container ready for transport.
The container is hung up by its lifting loops and blown up with air before it is filled with bulk material from a storage bin. The container is filled while it is hanging in such a position that most of the load is carried by the lifting loops during the filling operation, even though the container bottom touches a floor, conveyer belt or the like.
The apparatus comprises a funnel for filling of bulk material, a filling pipe, a pipe for supplying air and holding devices for the flexible container. Such apparatuses are usually equipped with some means for removing dust. The apparatus may also comprise a storage bin having a flap for emptying it and a batch weigher. The storage bin can also be connected to a large silo and/or supplying means for bulk material.
During the development of the flexible container it has been found that it is necessary to have filling methods and apparatuses adapted to the container in order to obtain optimal utilization of the container. The filling methods and apparatuses used for, for instance, 50 kilo bags have not been found applicable.
There already are some patents describing how these special problems can be attacked. British patent specification No. 1.475.019, describes a method and an apparatus for filling sacks having a volume of at least 250 liters. The sacks comprise an outer sack of strong load supporting material and an inner bag of impervious material. The filling pipe is put into the bag through its opening, which then surrounds the pipe at such a height above the floor, etc., that only the bottom of the sack rests on the floor. The inner bag is blown up by air before filling of the free-flowing material. By filling the inner bag with air it is pressed tightly against the outer sack which is standing upright, having maximum of its volume ready for filling, and without any special support. Filling of the free-flowing material is then carried out during complete or partial closure of the air supply. The apparatus used comprises a filling pipe, preferably telescopic, and it also comprises dust removing means and air supply means and a valve for regulating the supply of free-flowing material.
British patent application No. 2.022.545 relates to an apparatus for filling flexible containers. The container is first secured to at least two hooks by its lifting loops, and its inner bag is fastened to a fixed vertical down pipe around the filling pipe. The apparatus comprises means for hoisting or lowering the down pipe to which the bag is fastened. The filing pipe can be arranged in a stationary or movable supporting frame, the upper part of which is connected to a storage bin.
The apparatus according to the British patent has been used commerically for several years and has a large capacity, but in order to fully utilize this apparatus, several persons are needed to operate the apparatus and make the filled containers ready for transport.
The apparatus according to the British application is rather complicated and the required investment will be too large for small filling stations.
Fastening the container to the holding devices and connecting and disconnecting the inner bag will be laborious. To operate such an apparatus, including making the container ready for further transport, will also necessitate a relatively large amount of work for each container. In order to fully utilize the capacity of the apparatus, it should also be operated by several persons.
The increasing application of large flexible containers for transport of bulk material has created a need for filling apparatuses which both have a large capacity and at the same time are simple to operate and require few operators. Because the filling itself often is carried out at small distribution centers, it is important that the filling operation and the operation for making the container ready for further transport are simple. Large amounts of the goods packed in flexible containers are first transported in bulk from the plant to a distribution center, and these need apparatuses which can be applied to different types of goods and for flexible containers of different sizes.